* Add hard_link_static config option.

* Copy or hardlink file depending on an argument.

Modify the call sites for `copy_file` to account for the extra argument.

* Plug the config setting through to copy_file.

Don't apply the config option to theme's static directory.

* Update documentation.

* Backticks make no sense in this comment.

* Addressing PR comments.

* Be consistent with argument naming.

* chore: Update glob to 0.3

Signed-off-by: Igor Gnatenko <i.gnatenko.brain@gmail.com>

* chore: Update ws to 0.8

Signed-off-by: Igor Gnatenko <i.gnatenko.brain@gmail.com>

* Add check subcommand

* Add some brief documentation for the check subcommand

* Start working on parallel link checks

* Check all external links in Site

* Return *all* dead links in site

To also process the ones found in templates

Closes #669

This reverts commit 1815155c1d.

This feature was originally reported in #257 and got fixed in
3a2dab59743e8d193a80ddb1aa1932e1b5462322, however it seems this
got lost during development.

Closes #661
Ref #257

Close #633

Split sitemap when it is getting too big

To ensure we will get the right `content`
directory.
Fix #629

adding back default in rebuild

Fix #620

Closes #607

Fix #604

* Change the behavior of the template rendering:
    * Check if the template bare name is present
    * Check if the template is part of a theme
    * Fallback to defaults
* Change the behavior of the shortcode rendering:
    * Call the template rendering function
* Prepend `__zola_builtins/` to most of the default elements in `ZOLA_TERA`
* Add a test to verify the presence and content of a `404.html` page
from a theme's template

Closes #582

Closes #576

Closes #521

Closes #533